Performing electromagnetic (EM) scattering measurements in the presence of clutter sources or objects which can reflect or scatter electromagnetic or radar test signals or fields can adversely affect such measurements. The scattered or reflected signals or fields from the clutter source can interact or interfere with the desired scattered or reflected signals from the target under test. Conventional methods of vector background subtraction do not work effectively when there are large interactions between the target-under-test and the clutter source. Examples of such clutter sources are Target Support Systems used to mount Radar Cross Section (RCS) Targets in both indoor and outdoor RCS ranges. These supports can severely contaminate the RCS of the Target return, and, under certain common situations, can interact significantly with the target-under-test. The ability to identify such target support contamination and other clutter sources and the interaction between such clutter sources and the target would allow the removal of these contaminants and the retrieval of accurate RCS target data.
Currently known systems and methods for removing the effects of clutter sources involve hardware solutions, software solutions and a combination of hardware and software solutions. Hardware methods generally attempt to reduce the RCS of the clutter through shaping the clutter source, selecting the materials from which the clutter source is constructed, treatment of the materials of the clutter source or some combination of these techniques to substantially reduce or eliminate the scattering or contamination by the clutter source. Such hardware solutions may not completely eliminate the clutter contamination to desirable or acceptable levels. Even for large targets, a very small amount of clutter contamination may create an undesirable degradation in the data.
Software solutions may generally involve combinations of vector background subtraction, image editing and reconstruction and Doppler filtering. Software solutions typically cannot account for the interactions between the clutter and the target. Accordingly such solutions may be ineffective when these interactions are significant or common. For example, vector background subtraction involves a measurement of the clutter without the target, and then a measurement of the target in the presence of the clutter. Subtracting the latter from the former yields the target return and the interactions when both the clutter and target are present. Under certain conditions, these interactions can be as large a contaminant as the clutter alone, so the result can still be significantly degraded.